This invention relates generally to detergent compositions and cleaning compositions having enhanced detergency and cleaning capabilities. It relates more particularly to detergent and cleaning compositions containing the 2-phenyl isomer of linear alkylbenzene sulfonates in concentrations higher than were previously available in the prior art, owing to the discovery of the revolutionary catalyst and process for producing such isomers in high concentration, as detailed herein.
Chemical compounds useful for removing grease, oils, dirt and other foreign matter from various surfaces and objects have been known for some time, including the simple soaps which are manufactured by the saponification of oils (including animal fats and vegetable oils). Saponification is essentially a process whereby aqueous alkali metal hydroxide is mixed with an ester (such as an animal fat or vegetable oil) to cause de-esterification of the ester with the formation of the alkali salt(s) of the carboxylic acid(s) from which the ester was derived, which salt(s) are typically very soluble in aqueous media. Importantly, the anion portions of such alkali salts of the carboxylic acid(s) include as part of their molecular structure a hydrophilic portion, i.e., the carboxylate function, which is highly attracted to water molecules. Such salts also include a hydrophobic portion as part of their molecular structure, which is typically a hydrocarbon-based portion containing between about 12 and 22 carbon atoms per molecule. Such salts are commonly referred to by those skilled in the art as xe2x80x9csalts of fatty acidsxe2x80x9d, and are often commonly referred to by laypersons as xe2x80x9csoapxe2x80x9d. Aqueous solutions of salts of fatty acids are very effective at causing grease, oils, and other normally water-insoluble materials to become soluble and thus capable of being rinsed away, thus leaving behind a clean substrate which may typically comprise a tabletop, countertop, article of glassware or dinnerware, flatware, clothing, architecture, motor vehicle, human skin, human hair, etc.
While the industries for the production of such soaps from fats and oils are now well-established, saponification chemists and other workers have continuously sought improved chemistry for rendering materials which are not normally soluble in aqueous media to become soluble therein. Towards this end, a wide variety of materials have been identified by those skilled in the art, with the common denominator of such materials being that the materials all contain a hydrophobic portion and a hydrophilic portion in their molecular structures.
One family of materials that have been identified as suitable soap substitutes are the linear alkylbenzene sulfonates (xe2x80x9cLAB sulfonatesxe2x80x9d). The LAB sulfonates in general are exemplified as comprising a benzene ring structure having a hydrocarbyl substituent (or xe2x80x9calkyl substituentxe2x80x9d) and a sulfonate group bonded to the ring in the para position with respect to one another. The length of the hydrocarbon chain of the alkyl substituent on the ring is selected to provide a high level of detergency characteristics while the linearity of the hydrocarbon chain enhances the biodegradability characteristics of the LAB sulfonate. The hydrocarbyl substituent may typically contain 6, 7, 8, 9, 10, 11, 12, 13, 14 or 15 carbon atoms (the xe2x80x9cdetergent rangexe2x80x9d) in a substantially linear arrangement, and may be attached to the benzene ring through a conventional Friedel-Crafts alkylation process using a corresponding olefin and employing a Lewis acid catalyst such as aluminum chloride and conditions known to those skilled in the art as useful for such alkylations. Various alkylation processes useful for production of alkylbenzenes are described in U.S. Pat. Nos. 3,342,888; 3,478,118; 3,631,123; 4,072,730; 4,301,316; 4,301,317; 4,467,128; 4,503,277; 4,783,567; 4,891,466; 4,962,256; 5,012,021; 5,196,574; 5,302,732; 5,344,997; and 5,574,198, as well as European patent application 353813 and Russian patent 739,046, the entire contents of which are incorporated herein by reference thereto.
Once a hydrocarbyl radical has been appended to a benzene ring in accordance with the foregoing, the resulting linear alkylbenzene must subsequently be sulfonated in order to produce a finished detergent material that is capable of solubilizing grease, oils, dirt, and the like from various substrates, such as dishes, motorized vehicles, hard surfaces, architecture, and fabrics, to name but a few. Sulfonation is a known chemical process whose reactants and conditions are known to those skilled in the chemical arts. Through the process of sulfonation, a sulfonate group is caused to become chemically bonded to a carbon atom in the benzene ring structure of the linear alkylbenzene, thus providing the molecule as a whole with a hydrophilic sulfonate group in addition to the hydrophobic hydrocarbyl portion.
It is known that during the course of mono-alkylation of the benzene ring to introduce a hydrocarbon tail into the molecular structure, several structural isomers are possible in which the benzene ring is attached to various points along the hydrocarbon chain used. It is generally believed that steric effects of the mono-olefin employed play a role in the distribution of isomers in the mono-alkylated product, in addition to the catalyst characteristics and reaction conditions. Thus, it is possible for a single benzene ring to become attached to, say, the 2, 3, 4, or 5 positions in a 10 carbon atom linear mono-olefin, with a different alkylbenzene isomer being produced in each such case. Sulfonation of such different materials results in as many different alkylbenzene sulfonates, each of which have different solubilization capabilities with respect to various oils, grease, and dirt, etc.
The sulfonates of the 2-phenyl alkyl isomers are regarded by those skilled in the art as being very highly desirable materials, as sulfonated linear alkylbenzene detergent materials made from sulfonation of the 2-phenyl alkyl materials have superior cleaning and detergency powers with respect to the sulfonation products of other isomers produced during the alkylation. The general structure of the most desired 2-phenyl alkyl isomer products may be defined as: 
which in a preferred embodiment has n equal to any integer selected from the group consisting of: 5, 6, 7, 8, 9, 10, 11, and 12. Since the Friedel-Crafts type alkylation employed to produce 2-phenyl alkyl isomers according to the invention may often utilize a mixture of olefins in the detergent range (C8 to C15), a distribution of various alkylbenzenes results from such alkylation. The present invention is therefore in one broad respect concerned with the use of sulfonated 2-phenyl alkylbenzenes derived from the alkylation of benzene, preferably using xcex1-mono olefins having a carbon number distribution in the detergent range, in detergent formulations.
As mentioned above, a 2-phenyl alkylbenzene is but one possible structural isomer resulting from the alkylation of benzene with an olefin, and a mixture of 2-phenyl alkylbenzenes results from the alkylation of benzene using as reactants a feed which includes a mixture of olefins in the detergent range. This may be due to resonance stabilization which permits effective movement of the double bond in an activated olefin/Lewis acid complex. Generally speaking, the collection of all isomeric products produced from the alkylation of benzene with a mixture of olefins in the detergent range is commonly referred to by those of ordinary skill in the art as xe2x80x9clinear alkylbenzenesxe2x80x9d, or xe2x80x9cLAB""sxe2x80x9d. Frequently, those skilled in the art use xe2x80x9clinear alkylbenzenesxe2x80x9d or xe2x80x9cLAB""sxe2x80x9d interchangeably with their sulfonates. It is common for people to say LAB""s when they are actually referring to sulfonated LAB""s useful as detergents.
Typically, LAB""s are manufactured commercially using classic Friedal-Crafts chemistry, employing catalysts such as aluminum chloride, or using strong acid catalysts such as hydrogen fluoride, for example, to alkylate benzene with olefins. While such methods produce high conversions, the selectivity to the 2-phenyl isomer in such reactions as known in the prior art is low, generally being about 30% or less. LAB""s with a high percentage of the 2-phenyl isomer are highly desired because such compounds when sulfonated have long xe2x80x9ctailsxe2x80x9d which provide enhanced solubility and detergent properties.
In one aspect the present invention provides a method and catalyst for LAB production having high substrate olefin conversion, high selectivity to 2-phenyl isomer LAB production, and employing a catalyst having long lifetimes and easy handling. Through use of this aspect of the invention, 2-phenyl alkylbenzenes may be produced in yields in excess of 80.0% on the basis of catalyst selectivity.
More importantly, the present invention provides detergent compositions and cleaning formulations made with a component that comprises a mixture of sulfonated alkylbenzenes in which the hydrocarbon groups that are bonded to the benzene ring may comprise any number of carbon atoms in the detergent range and in which at least 80% (weight basis) of the sulfonated alkylbenzene isomers present have the phenyl group attached to the hydrocarbon group in the 2 position of the hydrocarbon group. The invention provides detergent compositions and formulations which are formed from an alkylbenzene sulfonate component that comprises a mixture of: 1) a first alkylbenzene sulfonate component comprising 2-phenyl alkylbenzene sulfonates in which 2-phenyl alkylbenzene sulfonate isomers comprise at least 80% of all alkylbenzene sulfonate isomers present; and 2) a second alkylbenzene sulfonate component comprising either: a) alkylbenzene sulfonates in which isomers having the benzene ring attached to a linear alkyl group at a position other than the alkyl group""s 2 position comprise at least 70% of all alkylbenzene sulfonate isomers present; or b) branched alkylbenzene sulfonates, or a combination thereof.
Branched alkylbenzene sulfonates may be introduced into a formulated product according to the invention in one of two ways. First, a portion of the linear olefin feedstock used in the alkylation reaction of the benzene ring may be replaced by branched olefin(s), to provide an alkylbenzenes mixture for sulfonation in which the alkylbenzenes contain a selected amount of branched alkylate. The second method of providing branched alkylbenzene sulfonates in a finished formulation according to the invention is when branched alkylbenzene sulfonates purchased on the open market are used as a blending component in the production of a finished product according to the invention. Thus, by either blending or providing branching in the alkylation reaction product, it is possible to provide a wide range of the amount of branched alkylbenzene sulfonates in a finished formulation according to the invention; however, it is preferable that the branched isomers comprise any amount less than 50.0% of the total alkylbenzene sulfonate isomers present in a given formulation according to the invention, in another preferred form of the invention, branched isomers comprise any amount less than 15.00% of the total alkylbenzene sulfonate isomers present in a given formulation according to the invention; in yet another preferred form of the invention, branched isomers comprise any amount less than 2.00% of the total alkylbenzene sulfonate isomers present in a given formulation according to the invention.
In one preferred form of the invention, lower activity isomers (isomers other than the 2-phenyl isomers) of linear alkylbenzenes are present in the second alkylbenzene sulfonate component in any amount between 0.00% and 70.00%, including every hundredth percentage therebetween, by weight based upon the total weight of the second alkylbenzene sulfonate component.
In a preferred form of the invention, the second alkylbenzene sulfonate component may comprise alkylbenzene sulfonates in which isomers having the benzene ring attached to a linear alkyl group at a position other than the alkyl group""s 2 position comprise at least 50% of all alkylbenzene sulfonate isomers present.
In another preferred form of the invention, the second alkylbenzene sulfonate component may comprise alkylbenzene sulfonates in which isomers having the benzene ring attached to a linear alkyl group at a position other than the alkyl group""s 2 position comprise at least 40% of all alkylbenzene sulfonate isomers present.
In another preferred form of the invention, the second alkylbenzene sulfonate component may comprise alkylbenzene sulfonates in which isomers having the benzene ring attached to a linear alkyl group at a position other than the alkyl group""s 2 position comprise at least 30% of all alkylbenzene sulfonate isomers present.
Thus, an alkylbenzene sulfonate component according to yet another embodiment of the invention may contain sulfonated 2-phenyl alkylbenzenes in an amount of at least 30.00% by weight based upon the total weight of the sulfonated alkylbenzene component. In another form of the invention, an alkylbenzene sulfonate component may contain sulfonated 2-phenyl alkylbenzenes in an amount of at least 40.00% by weight based upon the total weight of the sulfonated phenyl alkylbenzene component. In yet another form of the invention, an alkylbenzene sulfonate component may contain sulfonated 2-phenyl alkylbenzenes in an amount of at least 50.00% by weight based upon the total weight of the sulfonated phenyl alkylbenzene component. In yet another form of the invention, an alkylbenzene sulfonate component may contain sulfonated 2-phenyl alkylbenzenes in an amount of at least 60.00% by weight based upon the total weight of the sulfonated phenyl alkylbenzene component. In yet another form of the invention, an alkylbenzene sulfonate component may contain sulfonated 2-phenyl alkylbenzenes in an amount of at least 70.00% by weight based upon the total weight of the sulfonated phenyl alkylbenzene component. In yet another form of the invention, an alkylbenzene sulfonate component may contain sulfonated 2-phenyl alkylbenzenes in an amount of at least 80.00% by weight based upon the total weight of the sulfonated phenyl alkylbenzene component.
By admixture with conventional mixtures of sulfonated linear alkylbenzene detergents, a mixture of sulfonated alkylbenzenes useful as components in detergent formulations having any desired 2-phenyl alkylbenzene isomer content in the range of between about 18.00% and 82.00%, including every hundredth percentage therebetween, may be produced using the materials provided according to the invention. Such mixtures of sulfonated alkylbenzenes are useful as a component in forming detergent and cleaning compositions useful in a wide variety of applications as later illustrated in the examples.
It has also been found that a catalyst according to this invention may be used in combination with an existing aluminum chloride or hydrogen fluoride alkylation facility to afford LAB having a higher 2-phenyl isomer content than would otherwise be available from such plant using conventional catalysts. Thus, an existing facility may be retrofitted to include one or more reactors containing the fluorine-containing mordenite of this invention. In this manner, a slip stream of reactants may be sent to the mordenite with effluent therefrom being introduced back into the conventional alkylation system. This embodiment has several advantages. For example, the cost of capital is minimized since conventional equipment will already be in place. Also, the retrofitted plant can produce higher 2-phenyl isomer LAB at the discretion of its operator, depending on need. That is, the plant need not produce strictly high 2-phenyl isomer LAB and can instead produce high 2-phenyl isomer at its discretion. In one embodiment, a slip stream of reactant is drawn and sent to one or more reactors containing fluorine-containing mordenite catalyst. The effluent from the fluorine-containing mordenite reactor may then be combined with effluent from the HF or aluminum chloride reactor to provide a product having a higher level of 2-phenyl isomer LAB than would otherwise be present in product from an HF or aluminum chloride reactor.
The invention, in one broad respect, is directed at cleaning formulations designed to cleanse a wide variety of surfaces or substrates and which possess increased tolerance to water hardness, wherein the formulations comprise an alkylbenzene sulfonate component having a much higher 2-phenyl isomer content than formulations previously available commercially, and other components known to be useful in formulating soaps, detergents, and the like.
The invention, in another broad respect is a process useful for the production of mono-alkylbenzene, comprising: contacting benzene with an olefin containing from about 8 to about 30 carbons in the presence of fluorine-containing mordenite under conditions such that linear monoalkylbenzene is formed.
In another broad respect, this invention is a process for the production of linear alkylbenzene, comprising: a) contacting benzene and an olefin having about 8 to about 30 carbons in the presence of a fluorine-containing mordenite to form a first linear alkylbenzene stream; b) contacting benzene and an olefin having about 8 to about 30 carbons in the presence of a conventional linear alkylbenzene alkylation catalyst to form a second linear alkylbenzene stream; and c) combining the first linear alkylbenzene stream and the second linear alkylbenzene stream form a third linear alkylbenzene stream, as well as the product made from this process.
In another broad respect, this invention is a process useful for the production of linear alkylbenzene, comprising: combining a product from a conventional linear alkylbenzene alkylation reactor with a product from a linear alkylbenzene alkylation reactor containing fluorine-containing mordenite.
In yet another broad respect, this invention is a process for the production of linear alkylbenzene, comprising: a) dehydrogenating a paraffin to form an olefin; b) sending a primary feed stream of benzene and the olefin through a conduit to a conventional linear alkylbenzene alkylation reactor; c) contacting the primary feed stream in the conventional linear alkylbenzene alkylation reactor with a conventional linear alkylbenzene alkylation catalyst under conditions effective to react the benzene and olefin to form a first linear alkylbenzene product; d) withdrawing a portion of the primary feed stream from the conduit and contacting the portion with a fluorine-containing mordenite under conditions effective to react the benzene and olefin to form a second linear alkylbenzene product; e) combining the first and second linear alkylbenzene products to form a crude linear alkylbenzene stream; and f) distilling the crude linear alkylbenzene stream in a first distillation column to separate benzene that did not react and to form a benzene-free linear alkylbenzene stream.
Such process may optionally include the steps of: g) distilling the benzene-free linear alkylbenzene stream in a second distillation column to separate any olefin and to form a linear alkylbenzene stream; and h) distilling the second olefin free alkylbenzene stream in a third distillation column to provide an overhead of a purified linear alkylbenzene product and removing a bottoms stream containing any heavies.
In another broad respect, this invention is a process useful for the production of monoalkylbenzene, comprising: introducing a feed comprising olefin having about 8 to about 30 carbons and benzene into a fluorine-containing mordenite catalyst bed under conditions such that monoalkylbenzene is produced, allowing benzene, olefin, and monoalkylbenzene to descend (fall) into a reboiler from the catalyst bed, removing monoalkylbenzene from the reboiler, and heating the contents of the reboiler such that benzene refluxes to further contact the fluorine-containing mordenite.
In yet another broad aspect, this invention relates to mordenite useful for alkylating benzene with olefin having a silica to alumina molar ratio of about 10:1 to about 100:1; wherein the mordenite has been treated with an aqueous hydrogen fluoride solution such that the mordenite contains from about 0.1 to about 4 percent fluorine by weight.
In yet another broad respect, the invention relates to a chemical mixture that contains linear alkylbenzenes produced using the process(es) and/or catalyst(s) taught herein; which chemical mixture is useful for producing a mixture of sulfonated linear alkylbenzenes which mixture contains a higher concentration of sulfonated 2-phenyl alkylbenzenes than previously available using prior art methods and catalysts.
In another broad respect, the invention comprises formulations for finished consumer and industrial strength compositions useful in or as: all-purpose cleaners, pine oil microemulsions, liquid dishwashing soaps, enzyme-based powdered laundry detergents, enzyme-free powdered laundry detergents, and the like, as it has been found that the use of sulfonated LAB mixtures having a higher content of the 2-phenyl isomer with respect to what has been heretofore available from the teachings of the prior art improves the effectiveness and cleaning action of all cleaning compositions which contain conventional sulfonated alkylbenzene detergents, be they linear or branched.
In another broad respect, the invention is a method useful for the preparation of fluorine-containing mordenite, comprising contacting a mordenite having a silica to alumina molar ratio in a range from about 10:1 to about 100:1 with an aqueous hydrogen fluoride solution having a concentration of hydrogen fluoride in the range of from about 0.1 to about 10 percent by weight such that the mordenite containing fluorine is produced, collecting the fluorine-containing mordenite by filtration, and drying.
The fluorine treated mordenite catalyst advantageously produces high selectivities to the 2-phenyl isomer in the preparation of LAB, generally producing selectivities of about 70 percent or more. Also, the fluorine treated mordenite enjoys a long lifetime, preferably experiencing only a 25 percent or less decrease in activity after 400 hours on stream. A process operated in accordance with the apparatus depicted in FIGS. 1 and 2 has the advantage that rising benzene from the reboiler continuously cleans the catalyst to thereby increase lifetime of the catalyst. In addition, this invention advantageously produces only low amounts of dialkylbenzene, which is not particularly as useful for detergent manufacture, as well as only low amounts of tetralin derivatives.
In another aspect the invention provides solid salts of alkylbenzene sulfonates, which solid salts may contain various cations for charge balance.
In another aspect the invention comprises finished detergent compositions useful for cleaning fabrics, dishes, hard surfaces, and other substrates that is formed from components comprising: a) an alkylbenzene sulfonate surfactant component present in any amount between 0.25% and 99.50% by weight based upon the total weight of the finished detergent composition, said component characterized as comprising any amount between 26.00% and 82.00% by weight based upon the total weight of the component, and including every hundredth percentage therebetween, of water-soluble sulfonates of the 2-phenyl isomers of alkylbenzenes described by the general formula: 
wherein n is equal to any integer between 4 and 16; and b) any amount between 0.50% and 99.75% of other components known to be useful in formulating soaps, detergents, and the like, wherein at least one of said other components is selected from the group consisting of: fatty acids, alkyl sulfates, an ethanolamine, an amine oxide, alkali carbonates, water, ethanol, isopropanol, pine oil, sodium chloride, sodium silicate, polymers, alcohol alkoxylates, zeolites, perborate salts, alkali sulfates, enzymes, hydrotropes, dyes, fragrances, preservatives, brighteners, builders, polyacrylates, essential oils, alkali hydroxides, ether sulfates, alkylphenol ethoxylates, fatty acid amides, alpha olefin sulfonates, paraffin sulfonates, betaines, chelating agents, tallowamine ethoxylates, polyetheramine ethoxylates, ethylene oxide/propylene oxide block copolymers, alcohol ethylene oxide/propylene oxide low foam surfactants, methyl ester sulfonates, alkyl polysaccharides, N-methyl glucamides, alkylated sulfonated diphenyl oxide, and water soluble alkylbenzene sulfonates having a 2-phenyl isomer content of less than 26.00%.
The mordenite catalyst of the present invention is useful as a catalyst in the production of LAB""s in accordance with the process of manufacturing LAB""s of this invention. LAB is useful as starting material to produce sulfonated LAB, which itself is useful as a surfactant.
Certain terms and phrases have the following meanings as used herein:
xe2x80x9cMeq/gxe2x80x9d means milliequivalents of titratable acid per gram of catalyst, which is a unit used to describe acidity of the catalysts. Acidity is generally determined by titration with a base, as by adding excessive base, such as sodium hydroxide, to the catalyst and then back titrating the catalyst.
xe2x80x9cConv.xe2x80x9d and xe2x80x9cConversionxe2x80x9d mean the mole percentage of a given reactant converted to product. Generally, olefin conversion is about 95 percent or more in the practice of this invention.
xe2x80x9cSel.xe2x80x9d and xe2x80x9cSelectivityxe2x80x9d mean the mole percentage of a particular component in the product. Generally, selectivity to the 2-phenyl isomer is about 70% or more in the practice of this invention.
xe2x80x9cDetergent rangexe2x80x9d means a molecular species which contains an alkyl group that comprises any number of carbon atoms: 8, 9, 10, 11, 12, 13, 14 or 15 per alkyl group, and includes LAB, LAB sulfonates, and mono-olefins.
xe2x80x9cSubstantially linearxe2x80x9d when referring to a hydrocarbon or alkyl chain that is part of an alkylbenzene, whether the alkylbenzene is sulfonated or not, means a hydrocarbon comprising between 7 and 16 carbon atoms linked to one another to form a straight chain, wherein the carbon atoms of said straight chain may have only hydrogen atoms or a methyl group bonded to them as appendages.
xe2x80x9cBranched alkylxe2x80x9d when referring to a hydrocarbon or alkyl chain that is part of an alkylbenzene, whether the alkylbenzene is sulfonated or not, means a hydrocarbon comprising between 4 and 16 carbon atoms linked to one another to form a straight chain, wherein one or more of the carbon atoms of said straight chain may have a hydrogen atom and any alkyl group other than a methyl group (including without limitation ethyl, propyl and butyl groups), bonded to them as appendages.
xe2x80x9cBranched alkylbenzenexe2x80x9d means a molecular species which comprises a branched alkyl chain appended to a benzene ring.
xe2x80x9cBranched alkylbenzene sulfonatexe2x80x9d means a water-soluble salt of a branched alkylbenzene that has been sulfonated.
xe2x80x9c2-phenyl alkylbenzenesxe2x80x9d means a benzene ring having at least one alkyl group attached to it, wherein the alkyl group comprises any number of carbon atoms between 7 and 16 (including every integral number therebetween) linked to one another so as to form a substantially linear chain and wherein the benzene ring is attached the alkyl group at a carbon atom that is adjacent to the terminal carbon of the substantially linear chain. Thus, the carbon atom that is attached to the benzene ring has a methyl group and another alkyl group attached to it in a 2-phenyl alkylbenzene.
xe2x80x9cSulfonated 2-phenyl alkylbenzenesxe2x80x9d means 2-phenyl alkylbenzenes as defined above which further comprise a sulfonate group attached to the benzene ring of a 2-phenyl alkylbenzene as described above, regardless of the position of the sulfonate group on the ring with respect to the location of the alkyl group; however, it is most common and preferred that the sulfonate group is attached to the benzene ring in the para-position with respect to the alkyl group.
xe2x80x9cLABxe2x80x9d means a mixture linear alkylbenzenes which comprises a benzene ring appended to any carbon atom of a substantially linear alkyl chain in the detergent range.
xe2x80x9cLAB sulfonatesxe2x80x9d means LAB which has been sulfonated to include an acidic sulfonate group appended to the benzene rings (thus forming a parent acid), and subsequently rendered to a form more soluble to aqueous solution than the parent acid by neutralization using any of alkali metal hydroxides, alkaline earth hydroxides, ammonium hydroxides, alkylammonium hydroxides, or any chemical agent known by those skilled in the art to react with linear alkylbenzene sulfonic acids to form water-soluble linear alkylbenzene sulfonates.
xe2x80x9c2-phenyl isomerxe2x80x9d means LAB sulfonates of 2-phenyl alkylbenzenes.
All percentages are expressed in terms of weight percent, unless specified otherwise.